Glad you made a friend!!, and sorry your rats have lice but your new toy for them made me lol. I suggest for the costume at least for the head the skeleton/base starting with a box and tape...thats how I made my joey dog suit head...you make balls of masking tape and stack/ball them making the round shape you need then you cover the balls of tape with more tape non sticky face up...I can give more in depth directions if you need. This kind of sculpting produces a structure that is light and strong. It also holds its shape perfectly which is a big problem for these types of costumes. For the bell shape I'd say the best option is getting a hoop skirt or making your own. For the stripes it depends how you wanna go. do you want it to be furry? You can either paint on the stripes with paint pens or acrylic paints or glue/ iron on other colored fabric. I suggest trying a few different technigues on small samples and seeing how you think they look before deciding. http://i80.photobucket.com/albums/j163/helendragon/Joey%20in%20the%20Dog%20suit/Picture005-1.jpg